The invention relates to a brush-type seal having a wire bundle, which is bent around a core ring in a U-shape and is held by a ring-shaped slotted tube at its bent section.
This type of a brush-type seal is known from German Patent (DE-PS) 36 06 284. It is formed by bendingly winding a brush wire around two pins arranged in parallel and fitting a U-shaped clamping tube over and around the bending points of the wire bundles. As a result, the wires are fixed. Subsequently, the wire bristles are cut in parallel with respect to the pins for producing two brush-type seals. Then, the brush-type seals may be bent into the required circular shape.
This known seal has a disadvantage in that the pressing power applied by the clamping tube may abate with time. This may cause slipping of individual bristles and the occurrence of irregularities and leaks. In addition, fastening devices for the seal may have negative effects on the brush-type seal because of non-uniform fastening forces.
As a result, it is an object of the invention to provide a brush-type seal which is easy to fasten and ensures a constant pressing power to be applied to the bristles in order to obtain a stable suspension and fixing of the bristles.
According to the invention, this object is achieved by providing an arrangement wherein the tube is enclosed on both sides under tension by two support rings joined together to form a housing that applies a required clamping force to the wire bundle via the joined support rings and the tube. The support rings are joined together by means of welding or soldering. This arrangement provides for a secure, simple to construct, brush type scaling arrangement.
The arrangement according to the invention has the advantage that the clamping of the brushes is taken over by the joined support rings, while the slotted ring-shaped tube, which surrounds the brushes directly, only provides for the protection of the bristles.
In a preferred embodiment of the invention, the joining of the partial support rings takes place by welding or soldering, whereby the prestressing or the pressing power onto the brushes is achieved by the thermally caused shrinkage. This pressing power remains constant and thus ensures the constant functioning of the brush-type seal. Resistance inert-gas welding is particularly suitable for this purpose.
In a further development of certain preferred embodiments of the invention, one of the support rings is equipped with a device for the fastening of the brush-type seals to other components. As a result, a simple and detachable connection is possible for connecting the brush-type seal at a housing part. Such a connection occurs without any clamping force repercussions on the seal and thus insures the operatability of the seal.
A further development of certain preferred embodiments of the invention provides that several support rings are arranged axially behind one another such that each wire bundle is provided between two support rings. Thus, double seals or multiple seals can be achieved with low space and fastening requirements.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.